Weird noise problem
 

I have had this car about a year now ( 951) and have gotten it in pretty good shape. When I first bought it, the rear suspension was bottoming out, like there were no torsion bars. The PO had receipts for new torsion bars that supposedly had been installed a year or so earlier. I checked with the shop that had installed them and they had no idea why the car was sitting so low. At any rate , rather than try an attempt at re-indexing or whatever was needed, I bought some coilovers and installed them. The car sits at a proper ride height now, and handles very well. Here's the problem, the rear end squeaks and groans like crazy. I have tried lubricating every point of contact and this seems to help temporarily.After about a hundred miles of driving, however, the noise is back. Now I have discovered something that is a little weird. I was driving over a mountain pass last week, enduring the noise, when I started to encounter some wet , slushy highway. After a few miles of wet highway, the noise stopped completely and did not return even after I was back on dry pavement. A few days later, the noise returned. So I tried a little experiment, I sprayed water up under the rear of the car into every area of the suspension. Guess what? The noise has stopped again. My theory is that the rubber bushings absorb water and it acts as a lubricant? How can I keep it wet under there? Anyone else have any ideas?

Try applying silicone to the bushing or replace them.

Maybe an explanation could apply.
ELEPHANT RACING Tech Topic, Polyurethane Bushings and Friction

John_AZ

Try spraying silicone on one bushing at a time to find out which one is doing the squeaky sound. Time consuming I know, but would save you money by replacing only the right bushing.

Cheers,
Larry

Thanks, guys...interesting article, John. If this car does have polyurethane bushings, they must have been added on by one of the PO's. Or did it come this way from the factory? All I know is ,when they get wet, they shut up. Guess I'll have to replace the bushings, but in the meantime I'll hose down the rear suspension before I drive it. I was planning to take this car down to Tucson for my annual trip, don't have time to fix it before I go, so I guess I'll just have to stop along the way and for an occasional 944 enema :rolleyes:.